In a conventional telecommunications switching network, a communication path must be established before distribution of call information messages, such as fax, EMAIL, or voice, can be distributed along the established path. A propagation delay occurs across the network when setting up and releasing a connection path. For example, the propagation delay across a 2,500 mile long network may be approximately 20 milliseconds, depending on protocol speeds. In order to set up and release a connection path, a connection request is sent across the network, a connection acknowledgment is returned, a disconnect request is sent with the call information, and a disconnect acknowledgment is returned. The total time for transmitter operation would be 80 milliseconds plus the time required to send the message over the network. For short message types, it takes longer to establish the connection path than the time it takes to actually send the message type.
The highest volume of messages in packet networks has been electronic mail with an average message size of approximately 2,000 bytes. Messages of this small size take about 0.5 seconds to be fully delivered, far longer than the delay of 20 to 60 milliseconds caused by one to three transit times at the speed of light over a 2,500 mile network. Facsimile transmission however has become by far the primary form of message distribution. Fax messages average 100 kilobytes, equivalent to about a first class U.S. mail letter of three pages. As technology advances, image and fax document movement will increase in traffic flow and gradually replace much of the paper flow carried today by the U.S. mail. Therefore, it is desirable to distribute these relatively short, high priority messages in a quicker and efficient fashion.
From the foregoing it may be appreciated that a need has arisen to transmit call information without the propagation delay of establishing and releasing a connection path. A need has also arisen for sending call information without first establishing a connection path between a source and a destination.